Method for modifying a casting resin and/or coating composition

ABSTRACT

Suggested is a method for modifying the rheology of a casting resin and/or coating composition, comprising the following steps: providing a composition comprising at least one monomer capable of forming a casting resin or coating upon polymerisation; and adding to said composition a working amount of a urea urethane obtained under specific conditions as a thixotropic agent,

FIELD OF INVENTION

The present invention concerns the area of polymers is related to amethod for modifying rheology of a casting resin and/or coatingcomposition.

TECHNOLOGICAL BACKGROUND

Particularly within the field of casting resins, which are used forvarious purposes, it is necessary to tailor the rheological propertiesof such compositions. Setting the desired consistency in suchcompositions is customarily accomplished through appropriate selectionof binders, solvents, and the amount of pigments and/or fillers. In manycases, however, setting the desired consistency by means of theaforementioned constituents is not enough. In such cases, the additionof what are called rheological additives or thixotropic agents isrequired. Their effect may be a reduction in viscosity to aidworkability, or an increase in viscosity, the latter also being referredto as thickening. An increase in viscosity of this kind may be achieved,for example, through the addition of thixotropic agents as thickeners.

For the stated applications, a large number of different organic orinorganic thickeners are described: In aqueous systems, it is primarilycellulose ethers, starch, natural hydrocolloids, synthetic biopolymers,polyacrylate thickeners, associative thickeners based on hydrophobicallymodified polymers such as polyethers, ether urethanes, polyacrylamides,and alkali-activated acrylate emulsions, or water-swellable inorganicthickeners that are used. Typical thickeners for non-aqueous systems,besides organic thickeners such as waxes and thixotropic resins, areinorganic thickeners such as magnesium oxide and magnesium hydroxide,for example, which are used primarily in unsaturated polyester resinsystems, or amorphous silicas and phyllosilicates such as organicallymodified bentonite. In the aqueous systems, and especially non-aqueoussystems, that are to be thickened, these thickeners develop theirviscosity-increasing effect immediately after incorporation and/ormixing.

Where, for example, amorphous silica is used as a thixotropic agent in aliquid or dispersion in order to produce a thickening effect within saidliquid or dispersion, hydrogen bonds may be formed between theindividual silica molecules. This produces a three-dimensional network,thereby possibly reducing the fluidity of the liquid or dispersion. Anetwork of this kind can be destroyed again by exposure to shearingforces, leading in turn to a reduction in viscosity of the liquid ordispersion. After a certain regeneration time, the viscosity of thesystem climbs again, since the silica molecules present in the liquid ordispersion once again form a three-dimensional network. Thistime-dependent and reversible process is generally referred to asthixotropy.

The thixotropic effect of thixotropic agents such as amorphous silica,for example, is utilized in order, for example, to prevent the saggingor running of resin solutions, sealing compounds, adhesives, coatingmaterials, filling compounds, and casting resins, but also in order togive a more viscous consistency to mineral oils, for example.

In certain systems, the thixotropic agent used, such as amorphoussilica, for example, has a tendency to settle. This is particularlycritical if systems of this kind containing thixotropic agent aretransported over a relatively long time in containers and so are subjectto mechanical loads such as shearing forces occurring. Customarily anattempt is made to counteract this unwanted behaviour on the part of thethixotropic agent by increasing the amount of agent used, in order thusto ensure the maintenance of the thixotropic effect, such as theretention of a three-dimensional network, formed by hydrogen bondsbetween silica molecules, even under at least minor mechanical load.However, increasing the amount used of the thixotropic agent in this waywithin the respective system often has the disadvantage that too high aconcentration can lead to disruptions in certain technical applicationsof the systems, possibly leading, for example, to unwanted mattingeffects in the case of lustrously formulated coating systems, or else toa reduction in strength in resin systems. Moreover, such an increase inthe amount of thixotropic agent used is particularly deleterious, or isnot possible, in systems inherently having a relatively high viscosity.

In systems of these kinds in particular, therefore, the amount ofthixotropic agent that can be used is fairly limited.

In some systems containing thixotropic agents, such as, for example, ina system which as well as the thixotropic agent such as amorphous silicaalso comprises an epoxy resin-based binder, and is admixed with a curingcomponent such as an amine, for example, there may be (competing)formation of hydrogen bonds between the amine and the thixotropic agentsuch as amorphous silica—other words, there may be adsorption of theadded curing component to the thixotropic agent. As a result, thethree-dimensional network formed beforehand by hydrogen bonds betweenthe individual silica molecules may be at least partly destroyed, andhence, in particular, the thixotropic effect of the thixotropic agentused may be significantly weakened.

One approach which aims to prevent any such at least partial destructionof such networks in systems containing thixotropic agents, and/or aimsto boost the thixotropic effect of the thixotropic agent used, lies inthe strengthening or stabilizing of the network within the systemsthrough addition of a thixotropy-increasing additive.

RELEVANT STATE OF THE ART

Thus, for example, DE 3706860 A1 discloses thixotropy-increasingadditives based on polyhydroxycarboxamides, which in combination withfumed silica, in solvent-borne systems, improve the incorporation of thesilica and increase and stabilize its thixotropic behaviour. Thesepolyhydroxycarboxamides, however, have certain disadvantages in somebinder compositions, as for example in epoxy resin-based binders. Adisadvantage of the thixotropy-increasing additives known from DE 37 06860 A1, though, is that their thixotropy-increasing effect is notenough, especially in compositions which are applied at high layerthicknesses, and that where amines are used as a curing component inthese compositions, the thixotropy-increasing effect of these additivesmay be significantly weakened.

Reaction products of an alkyd resin and a poly(ester) amide asthixotropic agents are known from WO 1999 023177 A1. Thepoly(ester)amide here may be obtained by reaction of a polycarboxylicacid with an amine. The amine in that case is necessarily an aromaticamine, i.e., an amine which is not capable of forming imidazoline and/ortetrahydropyrimidine units. However, the document contains neither anyreference to a use of the poly(ester)amide per se as a thixotropicagent, nor to a use of this polymer or of the reaction product as athixotropy-increasing additive. In accordance with this teaching, athixotropic effect is provided exclusively by the reaction product ofthe alkyd resin and the poly(ester)amide.

Moreover, the addition of a high molecular weight polyethyleneimine asthixotropy-increasing additive with a molecular weight of about 750 000g/mol is described in EP 0835910 A1. The usefulness of thisthixotropy-increasing additive is confined, however, to epoxyresin-based binder systems. A disadvantage of the high molecular weightpolyethyleneimines, however, is that on account of their high polaritythey have a high viscosity and are difficult to process and/or are ofonly limited or zero compatibility with many customarily employedbinders. Moreover, the high molecular weight polyethyleneimines are usedcustomarily in the form of an aqueous composition, this, however, beingdeleterious for the majority of solvent-containing compositions, sincewater may act catalytically and, especially in the case ofpolyurethane-based binders, there may be unwanted formation of gas.Furthermore, in polyester-based binders in particular, the storagestability of the high molecular weight polyethyleneimines is low.

EP 2970696 B1 (BYK) describes condensation products obtained by reactingat least one polymerized fatty acid or at least one reaction product ofat least two polymerized fatty acids and at least one polyamine havingat least two primary amino groups with at least one polyalkylenepolyamine for the same purpose. The thixotropic agents provide asufficient primary viscosity to a casted resin; however, viscosity isfound not being stable over the time, particularly at elevatedtemperatures.

Problem to be Solved

There is nevertheless a need for thixotropy-increasing additives,especially in combination with a thixotropic agent such as amorphous andmore particularly fumed silica, for example, which do not have the abovedisadvantages of the customarily employed thixotropy-increasingadditives.

It is an object of the present invention, therefore, to provide athixotropy-increasing additive which has advantages over the customarilyemployed thixotropy-increasing additives. More particularly it is anobject of the present invention to provide compositions comprising atleast one such thixotropy-increasing additive and also at least onethixotropic agent, these compositions having advantages over thecustomarily employed compositions, particularly in respect of thethixotropic effect of such compositions, which are used as adhesives,sealants, paints, or coating materials, more particularly as adhesives.More particularly it is an object of the present invention to provide acomposition which, in particular on account of the thixotropy-increasingadditive it comprises and also on account of the thixotropic agent itcomprises is suitable for enhancing the mechanical properties of thecompositions in the uncured, and in the cured, state, especially forincreasing their stability.

DESCRIPTION OF THE INVENTION

The invention concerns a method for modifying the rheology of a castingresin and/or coating composition, comprising the following steps:

-   (i) providing a composition comprising at least one monomer capable    of forming a casting resin and/or coating upon polymerisation; and-   (ii) adding to said composition a working amount of a urea urethane    as a thixotropic agent,    said urea urethane being obtained according to the following steps:-   (a) providing a monohydroxyl compound of formula (I)

R—OH  (I)

-   -   in which R is n-alkyl or isoalkyl containing 4 to 22 carbon        atoms, cycloalkyl containing 6 to 12 carbon atoms, aralkyl        containing 7 to 12 carbon atoms or a radical of the formula        C_(m)H_(2m+1)(O—C_(n)H_(2n))_(x)— or        C_(m)H_(2m+1)(OOC—C_(v)H_(2v))_(x)—, and m stands for an integer        of from 1 to 22, n stands for an integer of 2 to 4, x for an        integer of 1 to 15 and v means 4 or 5;

-   (b) providing a diisocyanate compound of formula (II)

OCN-[A]-NCO  (II)

-   -   in which A stands for a linear or branched alkylene radical        having 2 to 10 carbon atoms and/or a toluylene radical;

-   (c) reacting said monohydroxyl compound and said diisocyanate    compound to form a prepolymer;

-   (d) reacting said pre-polymer with a diamine compound, said diamine    compound being selected from the group consisting of    -   (d1) compound (II)

H₂N—[B]—NH₂  (III)

-   -   where B stands for a linear, branched and/or cyclic alkylene        group having 2 to 12 carbon atoms; and/or    -   (d2) compound (IV)

H₂N—(CH₂)_(a)-Ph-(CH₂)_(b)NH₂  (IV)

-   -   in which a and b represent independent from each other integers        from 1 to 5 and Ph stands for a phenyl radical,        wherein said pre-polymer and said diamine are reacted in a molar        ratio of 1:1.1 to 1:1.45.

It has surprisingly been found that with urea urethanes used inaccordance with the invention, it is possible to achieve an increase inthe thixotropic effect induced when taken alone.

More particular the thixotropic agents are liquid and applicable also innon-aqueous solvent-borne to 100% systems. They can be added at everyproduction step and does not require special incorporation procedures(like organo-clays, amides, castor oil derivatives than may requirepre-gel preparation, grinding or temperature activation) other thansufficient mixing. The additives provide excellent structure to systemsto prevent sedimentation of pigments and extenders on storage. Theyprovide a thixotropic flow for excellent sag/levelling balance andstrong shear thinning flow behaviour for improved application behaviour

The urea urethanes have been found particularly useful when combinedwith another thixotropic agent, especially if the thixotropic agent isamorphous silica, such as fumed silica, for example, since in that casethe presence of urea urethane leads to a strengthening of the silicanetwork built up by the thixotropic agent in different binder systems.

Therefore in a specific embodiment the present invention also disclosesa casting resin composition comprising or consisting of:

-   (a) a monomer capable of forming a casting resin upon    polymerisation;-   (b) a first thixotropic agent; and-   (c) a second thixotropic agent, different from the first one,    wherein said first thixotropic agent is a urea urethane and said    second thixotropic agent is amorphous silica.

The urea urethanes used in accordance with the invention actas—increasing additives, especially in combination with at least oneother thixotropic agent and optionally at least one binder. It has inparticular been surprisingly found that by means of such strengtheningof the silica network built up by the thixotropic agent, it is possibleto prevent at least partial destruction of the network under moderatetemperature increase and/or moderate mechanical loads.

It has further surprisingly been found that through use of the ureaurethanes used in accordance with the invention as athixotropy-increasing additive, it is possible to replace or at leastsignificantly reduce the amount of other thixotropic agents that need beused in order to achieve at least the same thixotropic effect, therebymaking it possible to reduce the incidence of adverse propertiesassociated with a greater amount of additional thixotropic agent beingused, such as, for example, unwanted matting effects in the case oflustrously formulated casted resins for coating systems or cables, orreduced strength in binders.

It has further surprisingly been found that through use of the ureaurethanes used in accordance with the invention as athixotropy-increasing additive, it is possible to exert a positiveinfluence over the settling behaviour of any other additional thethixotropic agent especially if the thixotropic agent (B) is amorphoussilica, such as fumed silica, for example.

It has further surprisingly been found that with the urea urethanes usedin accordance with the invention, the thixotropic effect induced by anyother thixotropic agent can be boosted, especially if compositionscomprising these compounds and also at least one binder and optionally,moreover, at least one curing agent are provided that are used asadhesive or sealant, more particularly as adhesive, since at the sametime it is possible, as a result, to increase the binding power of thecured adhesive or sealant and so to increase the mechanical stability ofthe adhesively bonded or sealed assembly. This is especiallyadvantageous where such assemblies are used under high mechanicalstress.

More particularly it has surprisingly been found that where thecompositions of the invention are used as coatings they can be appliedin layer thicknesses of several millimetres to centimetres tosubstrates. Especially where coatings are applied in such layerthicknesses, it is necessary to use casting resins distinguished bysufficiently high viscosity and/or low fluidity, in order to meet therequirements of overhead use or application to a vertical plane withoutrunning away.

Definitions

In the course of the present invention the following definitions shallapply:

-   -   “casting resin composition” shall mean any a composition        comprising at least one monomer capable of forming a casting        resin upon polymerisation. Particularly such casting composition        is a coating composition. Therefore—if not otherwise        indicated—the terms “casting composition” and “coating” or        “coating composition” are used as synonyms and are exchangeable        without creating a new disclosure. More particular, the phrase        covers:        -   non-aqueous conventional solvent-borne to 100% clear and            pigmented coating systems, like            -   alkyd top-coats and primers;            -   epoxy primer, top coats, floor coatings;            -   polyurethane top coats, floor coatings;            -   polyester baking systems;        -   non-aqueous conventional solvent-borne to 100% clear and            pigmented casting resin, gelcoats, glass fibre reinforced            ambient cured resin systems based on            -   polyurethanes            -   epoxides;            -   PMMA            -   polyesters, and        -   PVC plastisols    -   “polymerisation” shall mean any process transforming the        monomers in a casting resin composition into the casting resins        (or polymers). This term shall have the same meaning as for        example “curing” or “hardening” or “cross-linking”.    -   “casting resin” shall mean any polymer obtained from the        polymerisation of a casting resin composition. The term shall        have the same meaning as “casted polymer”.    -   The terms “thixotropy” and “thixotropic agent” are known to the        skilled person and defined for example in Römpp Lexikon, Lacke        and Druckfarben, Georg Thieme Verlag 1998 and in Römpp        Chemie-Lexikon, Georg Thieme Verlag 1992.

Casting Compositions

A casting composition comprises certain monomers which are subjected topolymerisation (synonym: curing, hardening, cross-linking) to providepolymeric casted resins. Polymerisation can be induced by heat, UVradiation, catalyst or combinations of them. The process is well-knownto any person skilled in polymer chemistry. Notwithstanding this fact,reference is made for example to OSSWALD ET AL (ed.) (2003). “Materialsscience of polymers for engineers”. Hanser Verlag. pp. 334-335. ISBN978-1-56990-348-3.

The monomers used in accordance with the invention preferably havecross-linkable functional groups. Any customary cross-linkablefunctional group known to the skilled person is contemplated here. Moreparticularly the crosslinkable functional groups are selected from thegroup consisting of hydroxyl groups, amino groups, carboxylic acidgroups, and unsaturated carbon double bonds, isocyanates,polyisocyanates, and epoxides such as ethylene oxides. The monomers areexothermically or endothermically crosslinkable or curable, preferablyin a temperature range from −20° C. C. up to 250° C. Preferably themonomers are crosslinkable at room temperature or at temperatures in therange from about 15 to about 80° C.

Monomers for Preparing Resins

According to the present invention said casting resin can be selectedfrom the group consisting of polyester resins, polyurethane resins,epoxy resins, silicone resins, vinyl ester resins, phenol resins, acrylresins and their mixtures. Consequently the corresponding monomers areselected from the group consisting of esters, isocyanates, epoxides,silicones, vinyl compounds, phenols, (meth)acryl compounds and theirmixtures.

For expoxide-based resins glycidyl ethers which have terminal epoxidegroups and, within the molecule, hydroxyl groups as functional groupsare preferred as monomers. These are preferably reaction products ofBisphenol A and epichlorohydrin or of Bisphenol F with epichlorohydrin,and mixtures thereof. The curing or crosslinking of such monomers isaccomplished customarily through polymerization of the epoxide groups ofthe epoxide ring, through a polyaddition reaction in the form of anaddition of other reactive compounds as curing agents in stoichiometricamounts onto the epoxide groups, in which case, accordingly, thepresence of one active hydrogen equivalent per epoxide group isnecessary (i.e., one Hactive equivalent is needed per epoxide equivalentfor curing), or through a polycondensation via the epoxide groups andthe hydroxyl groups. Examples of suitable curing agents are polyamines,more particularly (hetero)aliphatic, (hetero)aromatic, and(hetero)cycloaliphatic polyamines, polyamidoamines, polyaminoamides, andalso polycarboxylic acids and their anhydrides. Suitable polyamines areall polyamines also used for preparing the reaction product, it beingpossible for this product to be used in turn as component for preparingthe condensation product. Where polyamines are used as curing agents,those suitable as curing agents are, for example and in particular, thepolyamines disclosed in EP 0 835 910 A1.

For polyester-based resins monomeric esters which are derived frompolyols such as, for example, ethylene glycol or 1,4-butanediol andoptionally at least monounsaturated dicarboxylic acids or dicarboxylicacid derivatives such as adipic acid and/or terephthalic acid arepreferred. Polyester-based resins, especially unsaturatedpolyester-based resins, are customarily obtainable from variouscombinations of saturated and unsaturated dicarboxylic acids,dialcohols, and, optionally, suitable monomers. The reactivity ofpolyester-based resins is determined primarily by the number of reactiveunsaturated C—C double bonds of the dicarboxylic acid used or of thedicarboxylic acid derivative used (e.g., maleic acid, maleic anhydride,and fumaric acid); a fraction of saturated dicarboxylic acids (e.g.,orthophtalic acid, phthalic anhydride, isophthalic acid, etc.) mayinfluence, for example, the solubility in styrene and also certain latermechanical properties of the end product. Examples of suitable curingagents for curing polyester-based resins, especially unsaturatedpolyester-based resins, are compounds which permit a radicalpolymerization as a curing reaction which is initiated, for example, bythe decomposition of organic peroxides. The peroxides decompose by wayof temperature or the presence of accelerators such as metallic salts,cobalt octoate for example. Since this is a radical polymerization,there is no need for stoichiometric provision of the polyester-basedresins and the curing agent to be used; in other words, the curingcomponent can be used in only small, preferably catalytic, amounts.

For vinyl ester-based resins monomers obtained from the reaction of anepoxide with at least one unsaturated monocarboxylic acid are preferred.Resins of these kinds are notable for the presence of at least oneterminally positioned C—C double bond. The curing of such vinylester-based resins may take place through a radical polymerization,initiated for example by the decomposition of organic peroxides. Theperoxides are decomposed via temperature or the presence of acceleratorssuch as metallic salts, cobalt octoate for example. Since this is aradical polymerization, there is no need for stoichiometric provision ofthe vinyl ester-based resins and the curing agent to be used; in otherwords, the curing component can be used in only small, preferablycatalytic, amounts.

For poly(meth)acrylate-based resins and/or resins based on at least one(meth)acrylate copolymer monomer mixtures or oligomer mixtures of estersof acrylic acid and of methacrylic acid are the preferred educts.Polymer build-up takes place via the reaction of the C—C double bonds ofthese monomers. The curing of such poly(meth)acrylate-based resinsand/or resins based on at least one (meth)acrylate copolymer may takeplace through a radical polymerization, initiated for example by thedecomposition of organic peroxides. The peroxides are decomposed viatemperature or the presence of accelerators such as metallic salts, suchas copper octoate, for example, or amines such asN,N-dimethyl-p-toluidine, for example. Since this is a radicalpolymerization, there is no need for stoichiometric provision of thepoly(meth)acrylate-based resins and/or resins based on at least one(meth)acrylate copolymer and the curing agent to be used; in otherwords, the curing component (D) can be used in only small, preferablycatalytic, amounts.

For polyurethane-based resins monomers are preferred obtained by apolyaddition reaction between hydroxyl-containing compounds such aspolyols (such as, for example, hydroxyl groups of polyesters orhydroxyl-containing polyethers and also mixtures thereof) and at leastone polyisocyanate (aromatic and aliphatic isocyanates or di- andpolyisocyanates). Customarily this requires a stoichiometric reaction ofthe OH groups of the polyols with the NCO groups of the polyisocyanates.However, the stoichiometric ratio to be used can also be varied, sincethe polyisocyanate can be added to the polyol component in amounts suchthat there may be an “over-crosslinking” or an “under-crosslinking”.

For a certain lacquer comprising one of the aforementioned resinscellulose nitrate represents a preferred solvent.

The casting compositions of the invention typically contain saidmonomers in an amount of about 20 to about 99 wt.-%, preferably in anamount of about 25 to about 95 wt. %, more preferably in an amount ofabout 30 to about 90 wt.-%. The remaining amounts are dedicated to thethixotropic agents and optionally to further additives, in particularcuring agents.

Where the casting compositions of the invention comprise at least onecuring agent, this agent is preferably suitable for crosslinking. Curingagents of this kind are known to the skilled person. To accelerate thecrosslinking, suitable catalysts may be added to the composition. Allcustomary curing agents known to the skilled person may be used forproducing the composition of the invention.

The compositions of the invention preferably comprise the curing agentsin an amount of about 1 to about 100 wt.-%, preferably in an amount ofabout 2 to about 80 wt. %, more preferably in an amount of about 5 toabout 50 wt.-%, based in each case on the total weight of the monomers.

Thixotropic Agents

The composition according to the present invention may comprise saidurea urethanes in an amount of from about 0.1 to about 20 wt.-%.,preferably from about 0.5 to about 10 wt.-% and more preferably fromabout 1 to about 5 wt.-%.

As far as two thixotropic agents are present in the composition theirratio by weight may range from about 25:75 to about 75:25, morepreferably about 40:60 to about 60:40. The most preferred ratio betweenurea urethanes and secondary thixotropic agents, particularly amorphoussilica is about 50:50. In contrast to the silica obtained bywet-chemical means, which usually possess very high internal surfaceareas, amorphous silica obtained by flame hydrolysis consist ofvirtually spherical primary particles having particle diameters oftypically 7 to 40 nm. The specific surface areas are preferably in arange from 50 to 400 m²/g, preferably in a range from 50 to 380 m²/g(Degussa Pigments text series, number 54). They have essentially only anexternal surface area. This surface is partly occupied by siloxanegroups, partly by silanol groups. The high proportion of free silanolgroups gives untreated fumed silica a hydrophilic character. The silanolgroups are capable of reversible construction of a silica network viathe development of hydrogen bonds, as a result of which there may be athixotropic effect. It is also possible, however, although moreexpensive, to carry out organic after-treatment of the hydrophilicsurface area of fumed silica, using, for example, silanes such asdimethyldichlorosilane, trimethoxyoctylsilane, or hexamethyldisilazane,in which case the major proportion of the silanol groups are saturatedby organic groups and hence the hydrophilic silica is renderedhydrophobic. The fumed silica can therefore be present in the form ofnon-organically modified fumed silica (hydrophilic silica) or ofhydrophobically modified fumed silica, or in the form of a mixture ofthese silica, particular preference being given to the non-organicallymodified fumed silica (hydrophilic silica).

Further Additives

The aforesaid compositions may comprise further additives such as forexample emulsifiers, flow control assistants, solubilisers, defoamingagents, stabilizing agents, preferably heat stabilizers, processstabilizers, and UV and/or light stabilizers, catalysts, waxes,flexibilisers, flame retardants, solvents, reactive diluents, vehiclemedia, resins, adhesion promoters, organic and/or inorganicnanoparticles having a particle size <100 nm, such as carbon black,metal oxides and/or semimetal oxides, process aids, plasticizers, solidsin powder and fibre form, preferably solids in powder and fibre formthat are selected from the group consisting of fillers, glass fibre,reinforcing agents, and pigments, and mixtures of the aforesaidadditives.

Urea Urethanes

Suitable monohydroxyl compounds for use as starting materials for theurea urethanes as disclosed above encompass linear or branched,aliphatic or aromatic alcohols having 4 to 22 and preferably 6 to 12carbon atoms and their alkylene oxide adducts, preferably adducts of onaverage 1 to 20, and preferably 2 to 10 mol ethylene oxide, propyleneoxide or their mixtures to one of the aforementioned alcohols.Particularly preferred are butanol (all isomers), pentanol, hexanol,heptanol, octanol, nonanol, decanol, undecanol, dodecanol, myristylalcohol, stearyl alcohol, cetyl alcohol, oleyl alcohol, erucyl alcohol,behenyl alcohol, phenol, benzyl alcohol and their technical mixtures andadducts of 1 to 20 mol, preferably 2 to 10 mol ethylene oxide and/or 1to 5, preferably 2 to 4 mol propylene oxide.

Particularly preferred, however, are alkyl polyalkylene glycol ethers,preferably alkyl polyethylene glycol ethers having a molecular weight offrom about 200 to about 1,000 Dalton, as for example methyl ethers(MPEG) or butyl ethers (BPEG) of PEG100, PEG200, PEG300, PEG350 orPEG500.

While the diisocyanate compound can be of aliphatic origin, thepreferred embodiments encompass aromatic or cycloaliphatic compounds ortheir mixtures, such as for example

-   -   Methylendiphenylisocyanat (MDI)    -   Toluoldiisocyanat (TDI)    -   Hexamethylendiisocyanat (HDI)    -   Isophorondiisocyanat (IPDI)    -   4,4-Dicyclohexylmethandiisocyanat (H12MDI)

Particularly preferred is toluylene diisocyanate (also cited as toluoldiisocyanate) which as available for example under the trademarkDesmodur® (COVESTRO) in the market. With regard to the performance ofthe end product a toluylene diisocyanate encompassing about 50 to about80 mol-% of the 2,4-isomer is particularly preferred.

Suitable diamine compounds encompass aliphatic, cycloaliphatic andaromatic diamines. A suitable diamine is for example

in which R′″ stands for hydrogen or a methyl group. The preferredspecies, however, is xylene diamine.

In a particular preferred embodiment the urea urethanes of the presentinvention are obtained by reacting MPEG300, MPEG350, BPEG300 or BPEG350with toluylene diisocyanate in a molar ration of from 1:1.2 to 1:1.4 toform a pre-polymer, which is subsequently reacted with xylene diamine toform the final product and is illustrated by the following formula:

Reaction Step 1: Formation of the Pre-Polymer

Key to the present invention is the formation of the pre-polymer,according to which said monohydroxyl compounds and said diisocyanatecompounds are reacted in a molar ratio of from about 1:1.00 to about1:1.45, preferably from about 1:1.10 to about 1:1.40.

Depending on the excess of diisocyanate pre-polymers containing one ortwo polyether groups are obtained. A disubstituted pre-polymer does notoffer a free reaction side for condensation with the amine group,remains as such in the final composition. Applicant, however, hasrecognized that the dissatisfying performance of the similar productsfrom the market is linked to the amount of unreacted pre-polymers. Byreducing the excess of diisocyanate the amount of pre-polymers availablefor further condensation with the diamine compound—as desired—issignificantly increased. This does not only lead to products of improvedperformance, but also to a composition which is different from themarket products and thus novel over the prior art.

Once the pre-polymer is formed it is advantageous removing the unreacteddiisocyanate for example by distillation in vacuum. Preferably theremaining pre-polymers show a content of unreacted diisocyanate of lessthan 0.5% by weight, and preferably about 0.1 to 0.2% by weight.

The specific reaction conditions are illustrated by—but not limitedto—the working examples.

Reaction Step 2: Formation of the Urea Urethane

Subsequently the pre-polymer thus obtained is reacted with a diaminecompound, preferably in at least one solvent, preferably an aproticsolvent such as dimethyl formamide, dimethyl acetamide, N-methylpyrrolidone or N-butyl pyrrolidone or similar alkyl pyrrolidones.Typically, the diamine compound—and optionally also the lithium salt—aredissolved in the solvent and placed into the reactor to which thepre-polymer is added. The preferred solvent is N-methyl pyrrolidone,since it is not listed under REACH.

The molar ratio between pre-polymer and diamine compound is adjusted toabout 1:1.2 to 1.2:1.

The solids amount can adjusted in broad ranges of from about 5 to about80% by weight, preferably about 20 to about 60% by weight, and morepreferred about 40 to about 50% by weight. The amount to 100% is thesolvent, optionally comprising small amounts of suitable additives asfor example corrosion inhibitors.

The urea urethanes prepared according to the present invention do notcontain either free isocyanate groups or free amino groups. They areaccordingly physiologically safe. Furthermore, no adverse side reactionsoccur with binders or fillers. The storage stability of these ureaurethane solutions prepared in this way is extraordinarily high and iscertainly 6 months or more at, normal storage temperature.

Surfactants

In a preferred embodiment, the reaction of the pre-polymer and thediamine compound takes place in the presence of a surfactant. To avoidany ambiguity a surfactant is understood being any substance capable oflowering surface tension (or interfacial tension) between two liquids orbetween a liquid and a solid. Suitable surfactants according to theinvention encompass, anionic, non-ionic, cationic, amphoteric andzwitterionic surfactants and of course their mixtures. Particularpreferred are surfactants of anionic type and/or showing an HLB value inthe range of 8 to 12.

Anionic Surfactants

Preferably, surfactants of the sulfonate type, alk(en)yl sulfonates,alkoxylated alk(en)yl sulfates, ester sulfonates and/or soaps are usedas the anionic surfactants. Suitable surfactants of the sulfonate typeare advantageously C₉₋₁₃ alkylbenzene sulfonates, olefin sulfonates,i.e. mixtures of alkene- and hydroxyalkane sulfonates, and disulfonates,as are obtained, for example, by the sulfonation with gaseous sulfurtrioxide of C₁₂₋₁₈ monoolefins having a terminal or internal double bondand subsequent alkaline or acidic hydrolysis of the sulfonationproducts.

Alk(en)yl sulfates. Preferred alk(en)yl sulfates are the alkali andespecially the sodium salts of the sulfuric acid half-esters of theC₁₂-C₁₈ fatty alcohols, for example, from coconut butter alcohol, tallowalcohol, lauryl, myristyl, cetyl or stearyl alcohol or from C₈-C₂₀ oxoalcohols and those half-esters of secondary alcohols of these chainlengths. Alk(en)yl sulfates of the cited chain lengths that comprise asynthetic straight chain alkyl group manufactured petrochemically arealso preferred. The C₁₂-C₁₆ alkyl sulfates and C₁₂-C₁₅ alkyl sulfates aswell as C₁₄-C₁₅ alkyl sulfates and C₁₄-C₁₆ alkyl sulfates areparticularly preferred on the grounds of laundry performance. The2,3-alkyl sulfates, which can be obtained from Shell Oil Company underthe trade name DAN™, are also suitable anionic surfactants.

Alk(en)yl ether sulfates. Sulfuric acid mono-esters derived fromstraight-chained or branched C₇-C₂₁ alcohols ethoxylated with 1 to 6moles ethylene oxide are also suitable, such as 2-methyl-branched C₉-C₁₁alcohols with an average of 3.5 mol ethylene oxide (EO) or C₁₂-C₁₈ fattyalcohols with 1 to 4 EO.

Ester sulfonates. The esters of alpha-sulfo fatty acids (estersulfonates), e.g., the alpha-sulfonated methyl esters of hydrogenatedcoco-, palm nut- or tallow acids are likewise suitable.

Soaps. Soaps, in particular, can be considered as further anionicsurfactants. Saturated fatty acid soaps are particularly suitable, suchas the salts of lauric acid, myristic acid, palmitic acid, stearic acid,hydrogenated erucic acid and behenic acid, and especially soap mixturesderived from natural fatty acids such as coconut oil fatty acid, palmkernel oil fatty acid or tallow fatty acid. Those soap mixtures areparticularly preferred that are composed of 50 to 100 wt. % of saturatedC₁₂-C₂₄ fatty acid soaps and 0 to 50 wt. % of oleic acid soap.

Ether carboxylic acids. A further class of anionic surfactants is thatof the ether carboxylic acids, obtainable by treating fatty alcoholethoxylates with sodium chloroacetate in the presence of basiccatalysts. They have the general formula:

RO(CH₂CH₂O)_(p)CH₂COOH

with R=C₁-C₁₈ alkyl and p=0.1 to 20. Ether carboxylic acids areinsensitive to water hardness and possess excellent surfactantproperties.

Sulfosuccinates. Overall preferred are anionic surfactants of thesulfosuccinate type. Sulfosuccinates represent sulfonation products ofsuccinic acid mono and diesters having the general formula

R¹OOC—CH₂—CH(SO₃X)—COOR²

With R¹=H, C₁-C₁₈ alkyl, R²=C₁-C₁₈ alkyl and X=alkali, alkaline earth,ammonium or alkyl ammonium. The preferred sulfosuccinates represent monoor diesters of line are or branched alcohols having 6 to 12 andpreferably 8 atoms, such as octanol or 2-ethylhexal alcohol. Thestructures may also incorporate polyalkylene glycol groups, such as forexample 1 to 10 moles of ethylene oxide and/or propylene oxide. Thesestructures (also called ether sulfosuccinates) are derived from therespective adducts of alkylene oxides to alcohols.

Nonionic Surfactants

Alkohol alkoxylates. The added nonionic surfactants are preferablyalkoxylated and/or propoxylated, particularly primary alcohols havingpreferably 8 to 18 carbon atoms and an average of 1 to 12 mol ethyleneoxide (EO) and/or 1 to 10 mol propylene oxide (PO) per mol alcohol.C₈-C₁₆-Alcohol alkoxylates, advantageously ethoxylated and/orpropoxylated C₁₀-C₁₅-alcohol alkoxylates, particularly C₁₂-C₁₄ alcoholalkoxylates, with an ethoxylation degree between 2 and 10, preferablybetween 3 and 8, and/or a propoxylation degree between 1 and 6,preferably between 1.5 and 5, are particularly preferred. The citeddegrees of ethoxylation and propoxylation constitute statistical averagevalues that can be a whole or a fractional number for a specificproduct. Preferred alcohol ethoxylates and propoxylates have a narrowedhomolog distribution (narrow range ethoxylates/propoxylates, NRE/NRP).

In addition to these nonionic surfactants, fatty alcohols with more than12 EO can also be used. Examples of these are (tallow) fatty alcoholswith 14 EO, 16 EO, 20 EO, 25 EO, 30 EO or 40 EO.

Alkylglycosides (APG®). Furthermore, as additional nonionic surfactants,alkyl glycosides that satisfy the general Formula RO(G), can be added,e.g., as compounds, particularly with anionic surfactants, in which Rmeans a primary linear or methyl-branched, particularly2-methyl-branched, aliphatic group containing 8 to 22, preferably 12 to18 carbon atoms and G stands for a glycose unit containing 5 or 6 carbonatoms, preferably for glucose. The degree of oligomerization x, whichdefines the distribution of monoglycosides and oligoglycosides, is anynumber between 1 and 10, preferably between 1.1 and 1.4.

Fatty acid ester alkoxylates. Another class of preferred nonionicsurfactants, which are used either as the sole nonionic surfactant or incombination with other nonionic surfactants, in particular, togetherwith alkoxylated fatty alcohols and/or alkyl glycosides, arealkoxylated, preferably ethoxylated or ethoxylated and propoxylatedfatty acid alkyl esters preferably containing 1 to 4 carbon atoms in thealkyl chain, more particularly the fatty acid methyl esters which aredescribed, for example, in Japanese Patent Application JP-A58/217598 orwhich are preferably produced by the process described in InternationalPatent Application WO-A-90/13533. Methyl esters of C₁₂-C₁₈ fatty acidscontaining an average of 3 to 15 EO, particularly containing an averageof 5 to 12 EO, are particularly preferred.

Amine oxides. Nonionic surfactants of the amine oxide type, for example,N-coco alkyl-N,N-dimethylamine oxide and N-tallowalkyl-N,N-dihydroxyethylamine oxide, and the fatty acid alkanolamidesmay also be suitable. The quantity in which these nonionic surfactantsare used is preferably no more than the quantity in which theethoxylated fatty alcohols are used and, particularly no more than halfthat quantity.

Gemini surfactants. The so-called gemini surfactants can be consideredas further surfactants. Generally speaking, such compounds areunderstood to mean compounds that have two hydrophilic groups and twohydrophobic groups per molecule. As a rule, these groups are separatedfrom one another by a “spacer”. The spacer is usually a hydrocarbonchain that is intended to be long enough such that the hydrophilicgroups are a sufficient distance apart to be able to act independentlyof one another. These types of surfactants are generally characterizedby an unusually low critical micelle concentration and the ability tostrongly reduce the surface tension of water. In exceptional cases,however, not only dimeric but also trimeric surfactants are meant by theterm gemini surfactants. Suitable gemini surfactants are, for example,sulfated hydroxy mixed ethers according to German Patent Application DE4321022 A1 or dimer alcohol bis- and trimer alcohol tris sulfates andether sulfates according to International Patent Application WO 96/23768A1. Blocked end group dimeric and trimeric mixed ethers according toGerman Patent Application DE 19513391 A1 are especially characterized bytheir bifunctionality and multifunctionality. Gemini polyhydroxyfattyacid amides or polyhydroxyfatty acid amides, such as those described inInternational Patent Applications WO 95/19953 A1, WO 95/19954 A1 and WO95/19955 A1 can also be used.

Cationic Surfactants

Tetraalkyl ammonium salts. Cationically active surfactants comprise thehydrophobic high molecular group required for the surface activity inthe cation by dissociation in aqueous solution. A group of importantrepresentatives of the cationic surfactants are the tetraalkyl ammoniumsalts of the general formula: (R¹R²R³R⁴N⁺) X⁻. Here R1 stands for C₁-C₈alk(en)yl, R², R³ and R⁴, independently of each other, for alk(en)ylradicals having 1 to 22 carbon atoms. X is a counter ion, preferablyselected from the group of the halides, alkyl sulfates and alkylcarbonates. Cationic surfactants, in which the nitrogen group issubstituted with two long acyl groups and two short alk(en)yl groups,are particularly preferred.

Esterquats. A further class of cationic surfactants particularly usefulas co-surfactants for the present invention is represented by theso-called esterquats. Esterquats are generally understood to bequaternised fatty acid triethanolamine ester salts. These are knowncompounds which can be obtained by the relevant methods of preparativeorganic chemistry. Reference is made in this connection to Internationalpatent application WO 91/01295 A1, according to which triethanolamine ispartly esterified with fatty acids in the presence of hypophosphorousacid, air is passed through the reaction mixture and the whole is thenquaternised with dimethyl sulphate or ethylene oxide. In addition,German patent DE 4308794 C1 describes a process for the production ofsolid esterquats in which the quaternisation of triethanolamine estersis carried out in the presence of suitable dispersants, preferably fattyalcohols.

Typical examples of esterquats suitable for use in accordance with theinvention are products of which the acyl component derives frommonocarboxylic acids corresponding to formula RCOOH in which RCO is anacyl group containing 6 to 10 carbon atoms, and the amine component istriethanolamine (TEA). Examples of such monocarboxylic acids are caproicacid, caprylic acid, capric acid and technical mixtures thereof such as,for example, so-called head-fractionated fatty acid. Esterquats of whichthe acyl component derives from monocarboxylic acids containing 8 to 10carbon atoms, are preferably used. Other esterquats are those of whichthe acyl component derives from dicarboxylic acids like malonic acid,succinic acid, maleic acid, fumaric acid, glutaric acid, sorbic acid,pimelic acid, azelaic acid, sebacic acid and/or dodecanedioic acid, butpreferably adipic acid. Overall, esterquats of which the acyl componentderives from mixtures of monocarboxylic acids containing 6 to 22 carbonatoms, and adipic acid are preferably used. The molar ratio of mono anddicarboxylic acids in the final esterquat may be in the range from 1:99to 99:1 and is preferably in the range from 50:50 to 90:10 and moreparticularly in the range from 70:30 to 80:20. Besides the quaternisedfatty acid triethanolamine ester salts, other suitable esterquats arequaternized ester salts of mono-/dicarboxylic acid mixtures withdiethanolalkyamines or 1,2-dihydroxypropyl dialkylamines. The esterquatsmay be obtained both from fatty acids and from the correspondingtriglycerides in admixture with the corresponding dicarboxylic acids.One such process, which is intended to be representative of the relevantprior art, is proposed in European patent EP 0750606 B1. To produce thequaternised esters, the mixtures of mono- and dicarboxylic acids and thetriethanolamine—based on the available carboxyl functions—may be used ina molar ratio of 1.1:1 to 3:1. With the performance properties of theesterquats in mind, a ratio of 1.2:1 to 2.2:1 and preferably 1.5:1 to1.9:1 has proved to be particularly advantageous. The preferredesterquats are technical mixtures of mono-, di- and triesters with anaverage degree of esterification of 1.5 to 1.9.

Amphoteric or Zwitterionic Surfactants

Betaines. Amphoteric or ampholytic surfactants possess a plurality offunctional groups that can ionize in aqueous solution andthereby—depending on the conditions of the medium—lend anionic orcationic character to the compounds (see DIN 53900, July 1972). Close tothe isoelectric point (around pH 4), the amphoteric surfactants forminner salts, thus becoming poorly soluble or insoluble in water.Amphoteric surfactants are subdivided into ampholytes and betaines, thelatter existing as zwitterions in solution. Ampholytes are amphotericelectrolytes, i.e. compounds that possess both acidic as well as basichydrophilic groups and therefore behave as acids or as bases dependingon the conditions. Especially betaines are known surfactants which aremainly produced by carboxyalkylation, preferably carboxymethylation, ofamine compounds. The starting materials are preferably condensed withhalocarboxylic acids or salts thereof, more particularly sodiumchloroacetate, one mole of salt being formed per mole of betaine. Theaddition of unsaturated carboxylic acids, such as acrylic acid forexample, is also possible. Examples of suitable betaines are the carboxyalkylation products of secondary and, in particular, tertiary amineswhich correspond to formula R¹R²R³N—(CH₂)_(q)COOX where R¹ is a an alkylradical having 6 to 22 carbon atoms, R² is hydrogen or an alkyl groupcontaining 1 to 4 carbon atoms, R³ is an alkyl group containing 1 to 4carbon atoms, q is a number of 1 to 6 and X is an alkali and/or alkalineearth metal or ammonium. Typical examples are the carboxymethylationproducts of hexylmethylamine, hexyldimethylamine, octyldimethylamine,decyldimethylamine, C_(12/14)-cocoalkyldimethylamine,myristyldimethylamine, cetyldimethylamine, stearyldimethylamine,stearylethylmethylamine, oleyldimethylamine,C_(16/18)-tallowalkyldimethylamine and their technical mixtures, andparticularly dodecyl methylamine, dodecyl dimethylamine, dodecylethylmethylamine and technical mixtures thereof.

Alkylamido betaines. Other suitable betaines are the carboxyalkylationproducts of amidoamines corresponding to formulaR¹CO(R³)(R⁴)—NH—(CH₂)_(p)—N—(CH₂)_(q)COOX in which R¹CO is an aliphaticacyl radical having 6 to 22 carbon atoms and 0 or 1 to 3 double bonds,R² is hydrogen or an alkyl radical having 1 to 4 carbon atoms, R³ is analkyl radical having 1 to 4 carbon atoms, p is a number from 1 to 6, qis a number from 1 to 3 and X is an alkali and/or alkaline earth metalor ammonium. Typical examples are reaction products of fatty acidshaving 6 to 22 carbon atoms, like for example caproic acid, caprylicacid, caprinic acid, lauric acid, myristic acid, palmitic acid,palmoleic acid, stearic acid, isostearic acid, oleic acid, elaidic acid,petroselinic acid, linolic acid linoleic acid, elaeostearic acid,arachidonic acid, gadoleic acid, behenic acid, erucic acid and theirtechnical mixtures with N,N-dimethylaminoethylamine,N,N-dimethylaminopropylamine, N,N-diethylaminoethylamine undN,N-diethylaminopropylamine, which are condensed with sodiumchloroacetate. The commercially available products include Dehyton® Kand Dehyton® PK (BASF) as well as Tego® Betaine (Goldschmidt).

Imidazolines. Other suitable starting materials for the betaines to beused for the purposes of the invention are imidazolines. Thesesubstances are also known and may be obtained, for example, by cyclizingcondensation of 1 or 2 moles of C₆ C₂₂ fatty acids with polyfunctionalamines, such as for example aminoethyl ethanolamine (AEEA) ordiethylenetriamine. The corresponding carboxyalkylation products aremixtures of different open-chain betaines. Typical examples arecondensation products of the above-mentioned fatty acids with AEEA,preferably imidazolines based on lauric acid, which are subsequentlybetainised with sodium chloroacetate. The commercially availableproducts include Dehyton® G (BASF).

The amount of surfactants is about 0.2 to about 2 mol, preferably about0.5 to about 1.5 mol, particularly preferred about 0.75 to about 1.25mol of surfactant, relative to the amine equivalent of the diamine used.

EXAMPLES Preparation Examples Example 1

Synthesis of monoisocyanate with polyethylene glycol monomethyl ether. Areactor is loaded with 208.8 gram of Desmodur® T80 (Toluenediisocyanate, 80% 2.4-isomer, 1.2 mol) and placed under a nitrogenblanket at 25° C. 350 gram of polyethylene glycol monomethyl ether (mw:350 g/mol) is added dropwise to the mixture while stirring. Thetemperature did not exceed above 35° C. After completing the additionthe reaction was followed on NCO content and stopped when the NCOcontent is in the correct range. The excess of TDI will be evaporated byvacuum and higher temperature. A slightly brown product was observed.The final NCO content is approximate 7.01% and the product has aviscosity of approximately 450 mPas. The final free TDI content is below0.1%

Synthesis of polyurea based on monoisocyanate from Example 1. Thereactor was loaded with 6.0 gram LiCl (1.2 wt.-%), 220.5 gram n-Butylpyrrolidone (so called NBP) and 20.6 gram m-xylene diamine (4.12 wt.-%,based on NCO content) and the mixture is while stirring heated up to100° C. All LiCl should be dissolved before addition of the monoadductstarts. A homogeneous mixture of 179.4 gram monoadduct obtained fromstep 1 and 73.50 gram NBP is added in approximate 1 hour. The NCO peakshould be disappeared (follow by IR). The reaction mixture is stirredfor at least 30 minutes. The reaction mixture is cooled down to roomtemperature when no NCO was found in IR. A clear low viscous product isobserved.

Example 2

Synthesis of mono isocyanate with polyethylene glycol monobutyl ether. Areactor is loaded with 208.8 gram of Desmodur® T80 (Toluenediisocyanate, 80% 2.4-isomer, 1.2 mol) and placed under a nitrogenblanket at 25° C. 382 gram of polyethylene glycol monobutylether (mw:382 g/mol) is added dropwise to the mixture while stirring. Thetemperature did not exceed above 35° C. After completing the additionthe reaction was followed on NCO content and stopped when the NCOcontent is in the correct range. The excess of TDI will be evaporated byvacuum and higher temperature. A slightly brown product was observed.The final NCO content is approximate 7.01% and the product has aviscosity of approximately 450 mPas. The final free TDI content is below0.1%

Synthesis of polyurea based on monoisocyanate from Example 2. Thereactor was loaded with 6.0 gram disodium dioctyl sulfosuccinate (1.2wt.-%), 220.5 gram n-Butyl pyrrolidone (so called NBP) and 20.6 gramm-xylene diamine (4.12 wt %, based on NCO content) and the mixture iswhile stirring heated up to 100° C. All sulfosuccinate should bedissolved before addition of the monoadduct starts. A homogeneousmixture of 179.4 gram monoadduct obtained from step 1 and 73.50 gram NBPis added in approximate 1 hour. The NCO peak should be disappeared(follow by IR). The reaction mixture is stirred for at least 30 minutes.The reaction mixture is cooled down to room temperature when no NCO wasfound in IR. A clear low viscous product is observed.

Examples 3 and 4 Preparation of a Casting Resin Composition with UreaUrethanes

80 g of a mixture of a polyacrylic acid and methylmethacrylate (20:80)were placed in a beaker and subjected with 0.25 g curing agent(N,N-Di-(2-hydroxyethyl)-p-toluidine) and 19.75 g of the urea urethaneaccording to Example 1 or Example 2 respectively. The mixture wassubjected to vigorous stirring over a period of 10 minutes untilhomogenous syrup was obtained. The intermediate thus obtained wassubjected with 0.75 g dibenzoylperoxide and stirred over another minute.

Examples 5 and 6 Preparation of a Casting Resin with Urea Urethane andAmorphous Silica

80 g of a mixture of a polyacrylic acid and methylmethacrylate (20:80)were placed in a beaker and subjected with 0.25 g curing agent(N,N-Di-(2-hydroxyethyl)-p-toluidine), 10.75 g of the urea urethaneaccording to Example 1 or Example 2 respectively and 9 g amorphoussilica. The mixture was subjected to vigorous stirring over a period of10 minutes until homogenous syrup was obtained. The intermediate thusobtained was subjected with 0.75 g dibenzoylperoxide and stirred overanother minute.

Comparative Example C1 Preparation of a Casting Resin Composition withPEI

80 g of a mixture of a polyacrylic acid and methylmethacrylate (20:80)were placed in a beaker and subjected with 0.25 g curing agent(N,N-Di-(2-hydroxyethyl)-p-toluidine) and 19.75 g of a linearpolyethyleneimine hydrochloride (M=10.000) obtained from Sigma. Themixture was subjected to vigorous stirring over a period of 10 minutesuntil homogenous syrup was obtained. The intermediate thus obtained wassubjected with 0.75 g dibenzoylperoxide and stirred over another minute.

Comparative Example C2 Preparation of a Casting Resin Composition withPEI and Amorphous Silica

80 g of a mixture of a polyacrylic acid and methylmethacrylate (20:80)were placed in a beaker and subjected with 0.25 g curing agent(N,N-Di-(2-hydroxyethyl)-p-toluidine), 10.75 g of a linearpolyethyleneimine hydrochloride (M=10.000) obtained from Sigma and 9 gamorphous silica. The mixture was subjected to vigorous stirring over aperiod of 10 minutes until homogenous syrup was obtained. Theintermediate thus obtained was subjected with 0.75 g dibenzoylperoxideand stirred over another minute.

Application Examples Example 7 Preparation of a Nitrocellulose WhiteTop-Coat with Urea Urethanes

198 g of a nitrocellulose coating without rheological additive wereplaced in a beaker and subjected with 2 g of the urea urethane accordingto Example 1 or Example 2 respectively. The mixture was subjected tovigorous stirring over a period of 10 minutes until homogenous materialwas obtained. The sample was stored for 24 h before evaluating itsrheological behaviour.

The results for the flow behaviour are shown in FIG. 1. The ureaurethane rheological additive according to Example 1 provided strongthixotropic flow behaviour to the nitrocellulose top-coat. This resultsin a significantly improved sag resistance with good levelling and flowproperties.

The results for the amplitude sweep are shown in FIG. 2. The ureaurethane rheological additive according to Example 1 provides a strongstructure to the nitrocellulose top-coat, i.e. storage modulus G′.Although oscillatory amplitude sweep tests results are used to definethe linear-viscoelastic-range (LVE-range) they give already anindication of the structure strength achieved with the example.

The results for the frequency sweep are shown in FIG. 3. Frequency sweeptest results performed within the LVE range determined by amplitudesweep confirm the strong structure provided by Example 1. The higher G′vs G″ at low frequencies indicate a good storage stability where the“solid-like” structure maintains pigments and extenders in suspensionand protects the sample from sedimentation during storage andpotentially transportation.

The results for oscillation recovery are shown in FIG. 4. Oscillationrecovery (also called structure recovery) shown in tan (delta), (ratioof G″/G′) confirm the more elastic structure of the coating sample withExample 1 at rest and the delayed recovery after shear. The testprocedure was according to the following protocol: Oscillation todetermine structure at rest (representative for behaviour at rest)followed by rotational measurement (represents application of thematerial) followed again by oscillation measurement to identify recoveryof the material after application. The delayed structure recovery aftershear indicates good levelling performance of the coating samplecombined with good sag resistance. The more fast the recovery the betterthe sag resistance and the lower the levelling properties.

For the additive according to Example 2 a similar results were found.

Example 8 Preparation of a 2c Polyurethane Top-Coat with Urea Urethanes

198 g of a conventional polyol (component A) without rheologicaladditive were placed in a beaker and subjected with 2 g of the ureaurethane according to Example 1. The mixture was subjected to vigorousstirring over a period of 10 minutes until homogenous material wasobtained. The sample was stored for 24 h before evaluating itsrheological behaviour. Its flow behaviour is shown in FIG. 5. For theurea urethane according to Example 2 a similar result was found.

Example 9 Preparation of a 2c Polyurethane Clear-Coat with UreaUrethanes

198 g of a conventional polyol (component A) without rheologicaladditive were placed in a beaker and subjected with 2 g of the ureaurethane according to Example 1. The mixture was subjected to vigorousstirring over a period of 10 minutes until homogenous material wasobtained. The sample was stored for 24 h before evaluating itsrheological behaviour. Its flow behaviour is shown in FIG. 6. For theurea urethane according to Example 2 a similar result was found.

Example 10 Preparation of a Polyurethane Casting System with UreaUrethanes

198 g of a 100% solids polyol with extender (component A) and withoutrheological additive were placed in a beaker and subjected with 2 g ofthe urea urethane according to Example 1. The mixture was subjected tovigorous stirring over a period of 10 minutes until homogenous materialwas obtained. The sample was stored for 24 h before evaluating itsrheological behaviour. Its flow behaviour is shown in FIG. 7. For theurea urethane according to Example 2 a similar result was found.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1: Flow behaviour with 1% rheological additive for a nitrocellulosecoating—white top-coat.

FIG. 2: Amplitude sweep with 1% rheological additive for anitrocellulose coating—white top-coat.

FIG. 3: Frequency sweep with 1% rheological additive for anitrocellulose coating—white top-coat.

FIG. 4: Oscillation recovery with 1% rheological additive for anitrocellulose coating—white top-coat.

FIG. 5: Flow behaviour with 1% rheological additive for two component PUcoating—white top coat

FIG. 6: Flow behaviour with 1% rheological additive for two component PUcoating—clear-coat

FIG. 7: Flow behaviour with 1% rheological additive for a polyol(filled) for casting applications

What claimed is:
 1. A method for modifying the rheology of a castingresin and/or coating composition, comprising the following steps: (i)providing a composition comprising at least one monomer capable offorming a casting resin and/or coating upon polymerisation; and (ii)adding to said composition a working amount of a urea urethane as athixotropic agent, said urea urethane being obtained according to thefollowing steps: (a) providing a monohydroxyl compound of formula (I)R—OH  (I)  in which R is n-alkyl or isoalkyl containing 4 to 22 carbonatoms, cycloalkyl containing 6 to 12 carbon atoms, aralkyl containing 7to 12 carbon atoms or a radical of the formulaC_(m)H_(2m+1)(O—C_(n)H_(2n))_(x)— orC_(m)H_(2m+1)(OOC—C_(v)H_(2v))_(x)—, and m stands for an integer of from1 to 22, n stands for an integer of 2 to 4, x for an integer of 1 to 15and v means 4 or 5; (b) providing a diisocyanate compound of formula(II)OCN-[A]-NCO  (II)  in which A stands for a linear or branched alkyleneradical having 2 to 10 carbon atoms and/or a toluylene radical; (c)reacting said monohydroxyl compound and said diisocyanate compound toform a pre-polymer; (d) reacting said pre-polymer with a diaminecompound, said diamine compound being selected from the group consistingof (d1) compound (II)H₂N—[B]—NH₂  (III)  where B stands for a linear, branched and/or cyclicalkylene group having 2 to 12 carbon atoms; and/or  (d2) compound (IV)H₂N—(CH₂)_(a)-Ph-(CH₂)_(b)NH₂  (IV)  in which a and b representindependent from each other integers from 1 to 5 and Ph stands for aphenyl radical, wherein said pre-polymer and said diamine are reacted ina molar ratio of 1:1.1 to 1:1.45.
 2. The method according to claim 1,comprising forming said casting resin into a product selected from thegroup consisting of transformers, isolators, capacitors, semiconductors,cables, muffles, prototypes and coatings and mixtures thereof.
 3. Themethod according to claim 2 wherein said casting resin is formed into acoating.
 4. The method of claim 1, wherein said monomer is selected fromthe group consisting of esters, isocyanates, epoxides, silicones, vinylcompounds, phenols, (meth)acryl compounds and mixtures thereof.
 5. Themethod of claim 1, wherein said urea urethane is derived from amonohydroxyl compound which is an alkyl polyalkylene glycol ether havinga molecular weight of from about 200 to about 1,000 Dalton.
 6. Themethod of claim 1, wherein said urea urethane is derived from adiisocyanate compound which is toluylene diisocyanate.
 7. The method ofclaim 1, wherein said urea urethane is obtained by reacting saidmonohydroxyl compound and said diisocyanate compound in a molar ratio offrom 1:1.05 to 1:6.
 8. The method of claim 1, wherein said urea urethaneis derived from a diamine compound which is xylene diamine.
 9. Themethod of claim 1, wherein said urea urethane is added to said at leastone monomer in an amount of from about 0.1 to about 20 wt.-%.
 10. Themethod of claim 1, wherein at least one further additive is added, saidadditive being selected from the group consisting of curing agents,emulsifiers, flow control assistants, solubilisers, defoaming agents,stabilizing agents, preferably heat stabilizers, process stabilizers,and UV and/or light stabilizers, catalysts, waxes, flexibilisers, flameretardants, solvents, reactive diluents, vehicle media, resins, adhesionpromoters, organic and/or inorganic nanoparticles having a particle size<100 nm, process aids, plasticizers, solids in powder and fibre form andmixtures thereof.